Atletico Madrid chief Miguel Angel Gil claims the Spanish club have rejected a £52 million bid for Sergio Aguero and Diego Godin from Chelsea.
Atletico also claim to have knocked back a £39 million offer from city rivals Real Madrid for their Argentina striker, nicknamed 'Kun' Aguero.
"Yesterday I received an offer of €45 million [£39 million] from Real Madrid for Aguero and I said no," Gil Marin told Spanish daily AS.
"This week, Chelsea offered us €60 million [£52 million] for 'Kun' and Godin and our answer was the same. I will not negotiate with Real Madrid or any other club for Aguero now or in the summer."
A spokesman for the La Liga side added: "Atletico have said no to the two offers because they believe in these two players."
Chelsea have been heavily linked with a move for Aguero despite the 22-year-old signing a new contract only recently. Uruguay defender Godin would provide excellent cover for the Blues' depleted defence.
However, the Premier League club refused to comment on the claims, a spokesman saying: "We never comment on transfer speculation, no matter how wild it is.''